A commercially available electronic high vacuum pump has bee tested on various types of mass spectrometers used at the Oak Ridge Gaseous Diffusion Plant. Considerable savings in operating and maintenance costs can be realized from the use of this pump. the greatest savings result from the elimination of the cold trap required for the diffusion pump whether it is cooled by liquid nitrogen or by mechanical refrigeration. additional savings results from the fact that the pump currently is usually an adequate indication of the pressure in the spectrometer tube and that a continuously running mechanical fore pump is not required.